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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Improving Data Quality: Development and Evaluation of Error Detection Methods

Lee, Nien-Chiu 25 July 2002 (has links)
High quality of data are essential to decision support in organizations. However estimates have shown that 15-20% of data within an organization¡¦s databases can be erroneous. Some databases contain large number of errors, leading to a large potential problem if they are used for managerial decision-making. To improve data quality, data cleaning endeavors are needed and have been initiated by many organizations. Broadly, data quality problems can be classified into three categories, including incompleteness, inconsistency, and incorrectness. Among the three data quality problems, data incorrectness represents the major sources for low quality data. Thus, this research focuses on error detection for improving data quality. In this study, we developed a set of error detection methods based on the semantic constraint framework. Specifically, we proposed a set of error detection methods including uniqueness detection, domain detection, attribute value dependency detection, attribute domain inclusion detection, and entity participation detection. Empirical evaluation results showed that some of our proposed error detection techniques (i.e., uniqueness detection) achieved low miss rates and low false alarm rates. Overall, our error detection methods together could identify around 50% of the errors introduced by subjects during experiments.
2

La vérification de patrons de workflow métier basés sur les flux de contrôle : une approche utilisant les systèmes à base de connaissances / Control flow-based business workflow templates checking : an approach using the knowledge-based systems

Nguyen, Thi Hoa Hue 23 June 2015 (has links)
Cette thèse traite le problème de la modélisation des patrons de workflow sémantiquement riche et propose un processus pour développer des patrons de workflow. L'objectif est de transformer un processus métier en un patron de workflow métier basé sur les flux de contrôle qui garantit la vérification syntaxique et sémantique. Les défis majeurs sont : (i) de définir un formalisme permettant de représenter les processus métiers; (ii) d'établir des mécanismes de contrôle automatiques pour assurer la conformité des patrons de workflow métier basés sur un modèle formel et un ensemble de contraintes sémantiques; et (iii) d’organiser la base de patrons de workflow métier pour le développement de patrons de workflow. Nous proposons un formalisme qui combine les flux de contrôle (basés sur les Réseaux de Petri Colorés (CPNs)) avec des contraintes sémantiques pour représenter les processus métiers. L'avantage de ce formalisme est qu'il permet de vérifier non seulement la conformité syntaxique basée sur le modèle de CPNs mais aussi la conformité sémantique basée sur les technologies du Web sémantique. Nous commençons par une phase de conception d'une ontologie OWL appelée l’ontologie CPN pour représenter les concepts de patrons de workflow métier basés sur CPN. La phase de conception est suivie par une étude approfondie des propriétés de ces patrons pour les transformer en un ensemble d'axiomes pour l'ontologie. Ainsi, dans ce formalisme, un processus métier est syntaxiquement transformé en une instance de l’ontologie. / This thesis tackles the problem of modelling semantically rich business workflow templates and proposes a process for developing workflow templates. The objective of the thesis is to transform a business process into a control flow-based business workflow template that guarantees syntactic and semantic validity. The main challenges are: (i) to define formalism for representing business processes; (ii) to establish automatic control mechanisms to ensure the correctness of a business workflow template based on a formal model and a set of semantic constraints; and (iii) to organize the knowledge base of workflow templates for a workflow development process. We propose a formalism which combines control flow (based on Coloured Petri Nets (CPNs)) with semantic constraints to represent business processes. The advantage of this formalism is that it allows not only syntactic checks based on the model of CPNs, but also semantic checks based on Semantic Web technologies. We start by designing an OWL ontology called the CPN ontology to represent the concepts of CPN-based business workflow templates. The design phase is followed by a thorough study of the properties of these templates in order to transform them into a set of axioms for the CPN ontology. In this formalism, a business process is syntactically transformed into an instance of the CPN ontology. Therefore, syntactic checking of a business process becomes simply verification by inference, by concepts and by axioms of the CPN ontology on the corresponding instance.
3

A obviação/referência disjunta em complementação sentencial : uma proposta sintático-semântica / Obviation/Disjoint Reference in sentential complementation : one syntactic/semantic approach

Meira, Vívian, 1981- 22 August 2018 (has links)
Orientador: Sonia Maria Lazzarini Cyrino / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Estudos da Linguagem / Made available in DSpace on 2018-08-22T08:47:05Z (GMT). No. of bitstreams: 1 Meira_Vivian_D.pdf: 1178142 bytes, checksum: e326a7771cea8102eee5851541fef4ea (MD5) Previous issue date: 2013 / Resumo: Esta tese investiga padrões de referencialidade em complementação sentencial no português, italiano e grego moderno, especialmente, o fenômeno conhecido como obviação ou referência disjunta. Esta é uma restrição atestada nas línguas e se caracteriza pelo fato de o sujeito da oração subordinada ser obrigatoriamente disjunto em referência ao sujeito da oração matriz. Tradicionalmente, assume-se que a obviação é uma propriedade de complementação subjuntiva ou um fenômeno resultante, juntamente com o controle, da competição entre formas finitas/não-finitas. No entanto, os dados não condizem com essas hipóteses, já que a obviação é exibida tanto em complementação indicativa quanto nos contextos de infinitivo flexionado. Além disso, nem todo contexto volitivo exibe obviação. Assumindo a teoria de seleção semântica e a versão minimalista de subcategorização (cf. Adger, 2004), propomos que a obviação, exibida em complementação sentencial, é uma restrição semântica exigida por três tipos de predicados, os causativos, os volitivos e os perceptivos físicos, que serão tomados como predicados modais no sentido de serem capazes de impor restrições semânticas aos seus complementos. Estes predicados foram denominados de predicados de obviação, por compartilharem entre si algumas propriedades, como denotar leitura eventiva/não-epistêmica, exigir sujeito pronominal na encaixada independente referencialmente do sujeito matriz e subcategorizar complemento TP. Argumentamos ainda que esses predicados, devido ao seu caráter modal, selecionam semanticamente um traço [obviativo], que é transmitido ao sujeito da encaixada. Predicados de obviação se distinguem de outro grupo de predicado modal, os predicados de controle, por estes não permitirem que o argumento da encaixada seja disjunto do sujeito matriz. Esses dois grupos se distinguem de outro grupo de verbos que permitem referência livre, constituído especialmente por predicados epistêmicos, declarativos, dentre outros, que denotam leitura epistêmica/proposicional e subcategorizam complemento CP. Sintaticamente este grupo de predicados se distingue dos predicados de obviação por subcategorizarem estruturas distintas, pois, enquanto estes têm complemento TP, aqueles selecionam complemento CP. Para explicar por que obviação e controle são exibidos pelo predicado volitivo, propomos que há dois tipos de acepções no volitivo nas línguas: o volitivo padrão, que seleciona controle e o volitivo causativo, que exige obviação. Defendemos que o complemento infinitivo flexionado selecionado por causativo e perceptivo é uma estrutura TP, o que o diferencia da estrutura de infinitivo flexionado selecionada por factivos/epistêmicos/declarativos, que é tomado como um CP. Estes permitem referência livre e aqueles exigem obviação. Nossa proposta é mostrar que a obviação, exibida em complementação sentencial, não é um fenômeno restrito às línguas românicas ou às línguas que exibem a distinção finito/não-finito, mas são uma restrição semântica imposta por predicados de obviação os seus complementos e, devido a isso, essa restrição semântica será exibida por línguas que dispõem desses contextos em complementação sentencial / Abstract: This thesis investigates patterns of referentiality in sentential complementation in Portuguese, Italian and Modern Greek, especially the phenomenon known as obviation or disjoint reference. This is a constraint attested in languages, and it is characterized by the fact that the subject of the subordinate clause must be disjoint in reference to the subject of the matrix sentence. Traditionally, obviation has been assumed to be a property of subjunctive complementation, or a phenomenon arising along with the control from the competition between finite/non-finite forms. However, the data are not consistent with these hypotheses, since obviation appears in indicative complementation and inflected infinitive contexts. Moreover, obviation is not displayed in every volitional context. Based on the theory of semantic selection and a minimalist version of subcategorization (cf. Adger, 2004), this thesis proposes that obviation, in sentential complementation, is a semantic constraint required by three types of predicates, the causative, volitional and physical perceptive predicates, which will be taken as predicates able to impose semantic constraints on their complements. These predicates are called obviation predicates, which share some common properties, as denoting eventive/non-epistemic reading, they require referentially independent subject pronouns in an embedded clause, and select a TP complement. We argue that these predicates, because of their modal character, select semantically a trace [obviative], which is transmitted to the subject in the embedded clause. Obviation predicates are distinguished from another group of modal predicates, control predicates, which do not allow, in an embedded clause, an argument referentially independent from the matrix subject. These two groups are distinguished from yet another group of verbs that allow free reference, specially constituted by epistemic, declarative predicates, among others, which denote an epistemic/propositional reading and select CP complements. Syntactically, this group can be distinguished from obviation predicates by selecting distinct structures, because while these have a TP complement, the former select CP complements. To explain why both obviation and control are displayed by volitional predicates, we propose that there are two types of volitional meanings in the languages: the default volitional that selects control, and the causative volitional, that requires obviation. Furthermore, we argue that the inflected infinitive complement selected by causative and perceptive verbs is a TP structure, and they require obviation, which differ from the inflected infinitive selected by factives/epistemic/declarative verb, which take CP complements and allows free reference. The purpose of this thesis is to show that obviation, in sentential complementation, is not a phenomenon restricted to the Romance languages, or languages that exhibit a distinction between finite and non-finite forms, but that it is a semantic constraint imposed by obviation predicates on their complements and, consequently, this constraint will appear in languages which have these contexts in sentential complementation / Doutorado / Linguistica / Doutora em Linguística

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